Characterization of the upward motion of an object immersed in a bubbling fluidized bed of fine particles

Investigation of single particle devolatilization in fluidized bed reactors by X-ray imaging techniques

“…In the past two decades, different non-invasive techniques have been developed to gain a deeper understanding of the interaction between fluidized bed and a relatively large freely moving particle. The most common methods are particle image velocimetry (PIV) [33,34], pressure signal analysis [22,35], radioactive particle tracking (RPT) [36][37][38][39], magnetic particle tracking (MPT) [15,32,40,41] and Lagrangian sensor system [42]. Most of these studies were carried out at ambient conditions using sensors or tracers to mimic the behaviour of a moving feedstock particle within the fluidized bed or investigating the hydrodynamic behaviour of the bed itself.…”

Improvement of the simulation of fuel particles motion in a fluidized bed by considering wall friction

“…These theoretical values were calculated using the well−known correlations of Davidson and Harrison [40] and Kunii and Levenspiel [1], for the bubbles and the dense phase velocity, respectively, using the same operating values of the bed as in the experiments (see Table 1). Further details on the calculation of the bubbles and dense phase velocities can be found in [6,7,9]. Figure 5 shows the results of the fuel particle velocity for the experiments and the simulations with and without the wall−friction term.…”

“…Figure 5 shows the results of the fuel particle velocity for the experiments and the simulations with and without the wall−friction term. In Figure 5a, the fuel rising velocity was related to the 20% [6,7] of the bubble velocity and the fuel sinking velocity was compared to the dense phase downwards velocity [6,9]. The sinking velocity depicted in Figure 5b was obtained by removing from the data analysis the downwards velocity associated to the vibration of the fuel particles in their sinking path, according to Soria-Verdugo et al [6].…”

“…In most of the studies available in the literature, the tracer particles are considered as objects, varying in density, shape and/or size to the bed material. It was observed that these objects sink to the bottom of the bed close to its lateral walls, following the motion of the dense phase, and rise through the center of the bed, affected by the bubbles ascension [3,4,5,6,7]. This motion pattern is characteristic of bubbling fluidized beds composed of a single mixing cell [5].…”

Experimental evaluation of the convection heat transfer coefficient of large particles moving freely in a fluidized bed reactor

“…The mixing of fuel particles in three-dimensional fluidized beds has been studied using a wide variety of experimental techniques, such as radioactive tracers [16,17], dry ice sublimation [18,19], magnetic tracer-particles [20], moisture released [21] and digital image analysis of the bed surface [22][23][24]. Concerning the mixing of fuel particles in pseudo-2D beds, the experimental techniques include emission of CO2 by carbon-loaded porous particles [25], magnetic particle tracking [26], and digital image analysis of phosphorescent particles [27]: strontium aluminate covered particles [28][29][30] or simply larger particles that could be distinguished from the dense phase [16,31].…”